Which type of steering is best for what vehicle?
Brakes and steering are the most critical parts of a car, even more than the power train. A car rolling down hill without the engine on can be just as much of a death trap when nobody can steer or stop it. The first thing to remember about steering is that it is all about geometry and durability of components. Before discussing which type of steering is best for what vehicle, we need a review of existing steering systems, attendant problems, and their potential for improvement.
Basic steering systems
There are two major areas: linkage and steering mechanism. Arrangements will vary, but most linkage systems consist of ball-type joints (tie rod ends, control arms), intermediate links (Pitman arm – also called “steering arm”, drag link), threaded adjuster sleeves, and links.
Major parts of a typical front end linkage system 
Front wheel suspension assembly – Left front wheel suspension of a Saab Quantum IV with double wishbones, showing kingpin axis, wheel hub, disc brake, steering arm and tie rod end 
There are two basic steering assemblies: recirculating ball bearings, and rack and pinion. The recirculating ball bearing system contains an “endless belt” of ball bearings that serve to reduce friction between the steering wheel shaft and the main linkage – Pitman arm – to the linkage assembly.
Typical recirculating ball assembly at the end of the steering shaft 
Rack and pinion steering consists of a straight toothed bar (rack) and a gear (pinion) that rolls the bar back and forth.
Rack and pinion concept 
The bar is attached to the tie rods that connect to the wheel, as depicted in the following diagram of a typical rack and pinion assembly.
Steering mechanism – rack and pinion 
The main advantage of the recirculating ball assembly is that the ball bearings reduce friction considerably. There is a steering wheel play and it is adjustable, usually by a slotted bolt with a securing nut mounted on top of the housing. The rack and pinion, while giving the driver a sense of directly steering the vehicle, it is not adjustable. Once the rack and pinion assembly wears out, they have to be replaced.References (Subject is indicated by URL – accessed 9 July 2011)  http://autorepair.about.com/library/bl244lib.htm  http://en.wikipedia.org/wiki/File:Suspension.jpg  Adapted from http://en.wikipedia.org/wiki/File:RecirculatingBall.png  http://en.wikipedia.org/wiki/Steering  http://autorepair.about.com/library/bl244lib.htm
INTERESTED IN LEARNING MORE ABOUT THIS TOPIC?